HostedSiteDemoThe nines
| Uptime | Per year | Per month | Per week | Per day |
|---|---|---|---|---|
| 99% | 3d 15h 36m | 7h 18m | 1h 40m 48s | 14m 24s |
| 99.5% | 1d 19h 48m | 3h 39m | 50m 24s | 7m 12s |
| 99.9% | 8h 45m 36s | 43m 48s | 10m 4.8s | 1m 26.4s |
| 99.95% | 4h 22m 48s | 21m 54s | 5m 2.4s | 43.2s |
| 99.99% | 52m 33.6s | 4m 22.8s | 1m 0.5s | 8.6s |
| 99.999% | 5m 15.4s | 26.3s | 6s | 0.9s |
Downtime = (1 − uptime ÷ 100) × period
A year here is 365 days (8,760 hours) and a month is one twelfth of that, 730 hours. Read more in what uptime SLAs really mean.
Frequently asked questions
How much downtime is 99.9% uptime?
99.9% uptime allows 8 hours, 45 minutes and 36 seconds of downtime a year, which is about 43 minutes and 50 seconds a month or 1 minute 26 seconds a day.
Is 99.9% uptime good for web hosting?
It is the usual standard for shared and VPS hosting, and fine for most small business sites. Online shops and apps where every minute costs money should look for 99.95% or 99.99%, or build redundancy across more than one server or region.
What does a hosting SLA pay if it misses the target?
Usually a service credit: a percentage of that month’s fee back, often 5 to 25%, and only if you claim it. It rarely covers your lost sales, so treat the SLA as a signal of quality, not insurance.
What is the uptime of two services together?
Multiply them. If your site needs a host at 99.9% and a database at 99.9%, together they give about 99.8%, roughly twice the downtime of either alone. The calculator shows this when you add a second service.